The (Brain) Power of Social Networks

Thank goodness for family and friends. Not only do they give you someone to rely on when you need help moving a couch or watching your dog while you’re on vacation, but they often positively influence your physical health—the friend who holds you to task on that daily run; the mother who keeps giving you new ways to prepare healthful foods; the co-worker whose smoking cessation inspires you to stay cigarette-free. Beyond the influence they have on your wellness that’s plain to see, though, you may also owe them a ‘thank you’ for a benefit of their company that you can’t—improved brain health.

The reasons are numerous (and impressive), and they are rooted in the impact your social network can have on reducing your stress level. “We know that chronic stress is linked to higher levels of cortisol (the “stress hormone”) which may result in fewer neurons; reduced elasticity in arteries (which can impede blood flow) and lower levels of something called BDNF, or brain-derived neurotrophic factor,” which is crucial for the functioning of nerve cells in the brain, says Cindy Geyer, M.D., medical director at Canyon Ranch in Lenox, Mass.

And the more your tension persists, the less GABA (gamma-aminobutyric acid)—a calming neurotransmitter that helps protect you from the effects of stress—your body produces. Social connections help you keep your stress in check—giving you a feeling of support, a source of laughter—which is especially powerful at fortifying your brain’s gray matter against these threats.

What’s more, says Dr. Geyer, those with strong social connections and less stress are more likely to have more volume in the hippocampus (related to memory storage) and the frontal lobe (which regulates decision-making and problem-solving) than their counterparts. “These individuals may also have more and larger neurons, and more glial cells—a type of brain cell that produces more GABA and neurotrophic factors, proteins that help neurons grow and survive,” she adds.

One evolutionary anthropologist, Robin Dunbar, Ph.D., has even correlated humans’ brain size (specifically the neocortex, which handles higher mental functions) with the size of social groups: The more relationships our early ancestors had, the bigger their brains, he found. This may be a key reason why our brains are so large, in fact (and too hefty for our bodies compared to other mammals).

A Georgetown University scanned the brains of people who undertook extreme acts of altruism—in this case, donating a kidney to a complete stranger—and found that the size of the right amygdala, which is where emotions are processed and integrated, was larger in the altruists and that they showed more empathy to people expressing fear. Research like this indicates that, “when you are in social networks and you reach out and connect, you may actually be able to change the size of your brain by your actions,” says Geyer.

How, exactly, does your goofy brother or dependable neighbor have this much influence? “If someone is there for you and it’s a positive interaction, then the hormone oxytocin is produced, and that actually blunts that physiologic response to stress,” says Dr. Geyer. “When we relax and connect with others in a positive way, cortisol levels go down and blood vessels respond by dilating and improving blood flow.”

Social connections can help ease depression, too, and even reverse the impact it has on the brain, she adds: “Research suggests that when depression is treated (in whatever way it’s treated—whether through connection to others, exercise, improved diet, antidepressants or psychotherapy) and it lifts, there’s a rebound in the volume in the hippocampus.” Studies have also shown that having more social support corresponds to fewer days of sadness and depression and more days of feeling vibrant. Some of

Some of depression’s common symptoms—mental fogginess, trouble with concentration and memory—are well-known to deplete brainpower, and untreated depression and chronic stress may even contribute to changes in the brain that play a role in mental disorders.

Relationships That Matter

Connecting with others doesn’t mean you have to be a social butterfly. What matters is the quality of your interactions, Geyer says. “If the contact with someone is hostile or unsupportive, it may actually exacerbate the stress response.” So while people who make you feel more supported and happier will in turn help make you healthier and possibly longer-lived, the reverse can also be true. Those in your life who are critical, demanding, upsetting or who make you feel depressed or anxious can be damaging to your health, physically and mentally.

And it’s worth remembering that feeling isolated and lonely is not the same as preferring to be on your own, in solitude. While humans crave connection with others, how much interaction we need and what kind vary a lot. One study out of the University of Michigan found that talking to someone for just 10 minutes a day improved memory and cognitive performance on tests, though the more interaction the study participants had, the better their test scores. Having a robust social network may be particularly important for maintaining mental ability in older people.

Does all that time spent on Facebook or your other favorite social networking website provide the same brain benefit? “It can be a useful adjunct to augment face-to-face connections,” says Dr. Geyer. “It really depends: If you use it to reconnect with friends you haven’t seen in years, stay in touch with others and share photos, and you still see these people in-person once in a while, then it might have a positive effect. But those who use virtual connections to replace the real thing may actually end up feeling more isolated and lonely.”